The present invention relates generally to audio level control and/or noise reduction systems, and in particular to a circuit arrangement for generating a level control signal using silicon diodes, the circuit being advantageously used for level controlled audio systems which are also designed to be associated with control signal generating circuits having germanium diodes.
Conventional circuits for deriving a level control signal from an audio input signal comprise a time constant circuit to which a rectified audio input is applied to generate a level control signal. The audio signal is conventionally rectified by a rectifier using germanium or silicon diodes as rectifiying elements. However, due to the significant difference in operating parameters between germanium and silicon diodes, the attack time of silicon constructed circuits differs significantly from those constructed of germanium diodes. Because of the inherent advantageous properties of silicon for integrated-circuits technology, silicon constructed circuitry is increasing in number with resultant undesirable consequences.